I can't reproduce this on vivid w.r.t the hang. For the "release all the devs" used in bcache setup; it's certainly awkward. Fundamentally, there's no path in sysfs that contains both the cache devs and the backing devs. And AFAIK, there is no way to know that the bcacheX devices is being cached by a specific cache set (/sys/fs/bcache/$UUID).
It's certainly possible to release all of the devices, but it does take some care: http://paste.ubuntu.com/12141060/ ** Changed in: bcache-tools (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1377130 Title: Crash at creation of bcache if caching size > backing size To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/bcache-tools/+bug/1377130/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs